I have finally sorted and cataloged all the panoramic images I took on my recent trip to Utah and Arizona. There are approximately 170 panoramas, and I have just begun the rendering. On our last day in Arizona, I decided … Continue reading
This article is to support the entrance pupil measuring technique outlined in Measuring the Entrance Pupil.
Zeiss provides entrance pupil data for the Loxia 21, 35, 50, and 85 mm lenses- see the Zeiss EP data in Table 1. Zeiss gives this data referenced from the image plane, and for the Sony A7, the flange to image plane distance is 18 mm.
I was not surprised to see the calculated focal length to vary from the nominal manufacturer’s value. However, I was surprised that the calculated focal length of the 85 mm lens was 91.8 mm- I repeated these measurements several times.
Before continuing and demonstrating the method outlined in my article Measuring the Entrance Pupil, I first need to introduce the calculator I use to determine the entrance pupil position.
In The Entrance Pupil And Its Importance, it was demonstrated that a requirement for high-quality image stitching was knowing the position of the entrance pupil. How do you find the entrance pupil?
- An educated guess will sometimes suffice, as the entrance pupil is the apparent position of the lens’ physical aperture as seen from the front of the lens. I have used this method many times when working with an unfamiliar lens.
- Look up the manufacturer’s data, not all, but some do include the entrance pupil position. For example, Zeiss Loxia 2.4/85 data sheet gives the position of the entrance pupil at 58.7 mm in front of the image plane.
- Look up the data on the Panotools Entrance Pupil Database.
- Never rely on the methods discussed in 2, 3, and 4- for all critical work, the entrance pupil must be measured.
It is so important, I will repeat it again: for critical work, the entrance pupil must always be measured, as the entrance pupil varies from lens to lens even of the same type.
SAN DIEGO, May 17, 2017 – Sony Electronics, a worldwide leader in digital imaging and the world’s largest image sensor manufacturer, has today announced two new additions to their growing lineup of full-frame E-mount lenses.
The new lenses include the FE 16-35mm F2.8 GM large aperture wide-angle zoom lens (model SEL1635GM) and the FE 12-24mm F4 G ultra wide-angle zoom lens (model SEL1224G). The FE 16-35mm F2.8 GM lens brings the incredible high-resolution and beautiful bokeh of Sony’s flagship G Master series to a wide 16-35mm focal length for exceptional landscapes, cityscapes, portraits and more, while the 12-24mm F4 G, Sony’s widest full-frame E-mount lens to date, offers a dynamic new perspective for all Sony E-mount shooters. In total, Sony’s full-frame E-mount lens lineup now covers from ultra-wide 12mm to super-telephoto 800mm (with teleconverter) focal length range.
New FE 16-35mm F2.8 GM Wide-Angle Zoom Lens
Why is carbon fiber used in photographic equipment, for example, tripods?
What is Carbon Fiber?
A carbon fiber is a long, thin strand of material about 0.0002-0.0004 in (0.005-0.010 mm) in diameter and composed mostly of carbon atoms. The carbon atoms are bonded together in microscopic crystals that are more or less aligned parallel to the long axis of the fiber. The crystal alignment makes the fiber incredibly strong for its size. Several thousand carbon fibers are twisted together to form a yarn, which may be used by itself or woven into a fabric. The yarn or fabric is combined with epoxy and wound or molded into shape to form various composite materials. Carbon fiber-reinforced composite materials are used to aircraft and spacecraft parts, racing car bodies, golf club shafts, bicycle frames, fishing rods, automobile springs, sailboat masts, and many other components where light weight and high strength are needed.